Many closure structures have been developed for two-compartment vials with the primary object thereof being the provision of means for easily actuating the vial so that the content of the two chambers therein can be mixed and used. A number of closure structures have been developed for similar purposes and some thereof are disclosed in U.S. Pat. Nos. 4,089,432, 4,180,173 and 4,194,640 and U.S. Pat. application Ser. No. 871,398 filed Jan. 23, 1978 all of which are assigned to the assignee of this application, and U.S. Pat. No. 2,908,274.
However, these patents and patent applications fail to disclose the combination of elements which are capable of producing the desired results achieved by the invention disclosed and claimed in this application. Specifically, they have not disclosed a closure structure having a stopper and a cap which, when combined, positively control the movement of the stopper relative to the vial during activation thereof, whereby the center plug of the two-compartment vial can be displaced in order to permit mixing of the contents of the vial without risking contamination of said contents.
Accordingly, a primary object of this invention is the provision of a closure structure for a two-compartment vial including a stopper means and cap means providing interengageable lock means whereby movement of the stopper means into the vial, during activation thereof, is positively limited and removal of the stopper means from within the vial thereafter is positively prevented.
A further object of this invention is the provision of a closure structure, as aforesaid, wherein the stopper means has a projecting portion of reduced diameter and the cap means has a sleeve portion snugly but slidably surrounding the projecting portion, and wherein the lock means is disposed upon and between said projecting portion and said sleeve portion, the sleeve portion being connected to the vial and being movable relative to the stopper means toward the vial before the interlocking engagement thereof occurs.